Audi R8 TDI Le Mans

From Le Mans victory to Audi showroom? A distinct possibility with this diesel superstar.

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Automobile manufacturers have long taken to the competitive test bed of the racetrack to improve their production-car brood. A good example of this highly beneficial track-to-road technology transfer from late in the last century was Honda's development of variable valve timing. This power-enhancing emissions-friendly technology that first appeared on the company's breakthrough mid-engine high-performance sports car, the Acura NSX, came directly from its development program for engines in Formula 1 racing.

And now, German luxury-car maker Audi is taking a more fuel-efficient technology from its successful motorsports program in the endurance races of the 24 Hours of Le Mans and the American Le Mans Series — a technology most U.S. citizens associate with big rigs and generators — and transferring it to the world of exotic, road-going, high-end sports cars...the diesel engine.

Enter the R8 TDI Le Mans. Audi claims this twin-turbocharged, 6.0-liter V-12 TDI (turbodiesel, direct-injected) machine produces a full 500 bhp and over 737 lb.-ft. of torque — the latter figure accomplished at a stunningly low 1750 rpm and maintained all the way up to 3000 rpm (redline is 4500) — that allow the R8 to sprint from a standstill to 60 mph in just over 4 seconds and on to a top speed of more than 186 mph.

While the race car's 12 cylinders are placed at a 90-degree V-angle, the road car's are situated at 60 degrees for less vibration. This configuration allows for an extremely compact engine — at 29.6 in. overall, it is only about 6.5 in. longer than the V-8 in the gasoline-powered Audi R8.

The addition of vermicular graphite in the casting process for the crankcase helps make the unit 40 percent more rigid, 100 percent more fatigue-resistant and around 15 percent lighter than one made of standard cast iron, says the company. This same technology is applied to all of Audi's V-6 and V-8 TDI engines.

The high-pressure (more than 28,000 psi) common-rail fuel-injection system and careful swirl variation of air within the combustion chamber combine to help maximize power production, reduce emissions and make for a more "acoustically refined" (quieter) engine.

Audi's proprietary AdBlue urea injection/catalytic converter/particulate system makes for a very clean diesel engine, one that the company says will not only meet the Euro 6 emissions standard that begins in 2014 but also will be 50-state compliant in the U.S. This hardware, along with the carbon-ceramic brake discs, is designed to "remain effective for the entire service life of the vehicle," says the company. In the case of the brakes, this means 186,411 miles (300,000 kilometers).

As is the fashion of several of today's exotic sports cars, the Audi's oil-burning V-12 is displayed under glass. A large center portion of the engine is a hefty section of polished aluminum, the sort of overbuilt-looking piece one would expect to find beneath the hood of a 1930s' Bugatti or Cadillac. Above the engine and just below the glass hangs a handsomely crafted carbon-fiber intake that begins as a single NACA duct inlet atop the roof that splits into two to feed air to each bank of cylinders. This setup does allow for some additional horsepower, says Audi, via a "ram air" effect.

A low-slung wing runs across the entire width of the rear decklid, along with a pair of air extractors at the rear diffuser.